Abstract: Various embodiments provide a processing module that calibrates a current-mode baseline correction system to account for features in an input device that lead to “offset” in output of a charge integrator used for sensing presence of an input object. The offset is a difference between a common mode voltage, which is the average voltage output of the charge integrator over a sensing cycle and a mid-rail voltage midway between high and low power supply voltages. Calibration is performed by adjusting an N-side and/or P-side current flow duration parameter until common mode voltage falls within a low offset window in which the offset is deemed to be sufficiently close to the mid-rail voltage. The resulting duration parameters are stored and used for current-mode baseline corrections when operating an associated sensor electrode for capacitive sensing.

Abstract: A capacitance measurement circuit cancels background capacitance while reducing charge leakage and supply ripples during reset phases and integrate phases. The capacitance measurement circuit operates a first switch into a linear mode causing a first resistance in the first switch, and after a delay, operates a second switch into a saturation mode causing a second resistance in parallel to the first resistance.

Abstract: Various embodiments provide a processing module that calibrates a current-mode baseline correction system to account for features in an input device that lead to “offset” in output of a charge integrator used for sensing presence of an input object. The offset is a difference between a common mode voltage, which is the average voltage output of the charge integrator over a sensing cycle and a mid-rail voltage midway between high and low power supply voltages. Calibration is performed by adjusting an N-side and/or P-side current flow duration parameter until common mode voltage falls within a low offset window in which the offset is deemed to be sufficiently close to the mid-rail voltage. The resulting duration parameters are stored and used for current-mode baseline corrections when operating an associated sensor electrode for capacitive sensing.

Abstract: A capacitance measurement circuit cancels background capacitance while reducing charge leakage and supply ripples during reset phases and integrate phases. The capacitance measurement circuit operates a first switch into a linear mode causing a first resistance in the first switch, and after a delay, operates a second switch into a saturation mode causing a second resistance in parallel to the first resistance.

Abstract: Systems and methods for sensing capacitances that are applicable to proximity sensor devices are provided. The systems and methods provide decreased implementation costs by reducing the number of output terminals required. Specifically, the systems and methods for sensing capacitances provide the ability to selectively activate indicating transducers, such as LEDs, with the same output terminals used for sensing capacitances. This reduces the need for additional, dedicated output terminals for activating the indicating transducers. As such, the system and method provides for efficient use of resources in proximity sensor devices.

Abstract: Systems and methods for sensing capacitances that are applicable to proximity sensor devices are provided. The systems and methods provide decreased implementation costs by reducing the number of output terminals required. Specifically, the systems and methods for sensing capacitances provide the ability to selectively activate indicating transducers, such as LEDs, with the same output terminals used for sensing capacitances. This reduces the need for additional, dedicated output terminals for activating the indicating transducers. As such, the system and method provides for efficient use of resources in proximity sensor devices.